Calling an API get request, can't access the function

I am trying to fetch API data using http client. I tried to follow this example https://docs.flutter.dev/cookbook/networking/fetch-data

But I am getting the following error whats on the image. Also, do I need to add ? after the Character? Because otherwise it won’t work, but all the examples I look at don’t have that?

class HttpManager {
   static String baseUrl = "https://rickandmortyapi.com/api/character";
   var client = http.Client();

   Future<Character?> getCharacters() async {
      var response = await client.get(Uri.parse(baseUrl));

      if (response.statusCode == 200) {
         return Character.fromJson(jsonDecode(response.body));
      }
   }

}

Then in my class I try to use it

>Solution :

Actually the function you have defined in HttpManager is not a static function that is why you can not call that function without creating a object of that class so you need to call the function like below

HttpManager().getCharacters();